Normalized Autocorrelation Function Based Doppler Signal Frequency Estimation Algorithm

The frequency of laser Doppler signal is hard to be detected accurately due to signal's weak strength and low SNR. This paper proposes a Doppler signal frequency estimation algorithm based on normalized autocorrelation function to improve robustness and evaluate the estimation precision of frequency. This algorithm can judge the maximum points of autocorrelation functions and thus obtain the period of the tested signal more accurately, and ultimately improve the frequency estimation precision. Laser Doppler velocity interferometer is adopted to collect the Doppler signals from a vibrating tuning fork, and the proposed algorithm is used to process these Doppler signals. The frequency measurement experiment results demonstrate that the proposed algorithm can calculate the frequency of Doppler signals which corresponds to the vibration frequency of the tuning fork. The algorithm also shows strong robustness under fast changing amplitude and lower SNR of Doppler signals.